A stent is a tubular device that is placed in a blood vessel
to keep it open. They are made of extremely thin and tiny metal tubes that are placed on tiny balloons which are steered to the proper site in the body on the end of a catheter
threaded into the body via a major vein
The metal tube is perforated so that the balloon can expand the target site in the vein or artery to make the blood vessel larger. A recent development has been to impregnate the stent with anticoagulants to prevent clotting.